Speed Limit Kattis Problem Solution In Java

import java.util.ArrayList;

import java.util.HashSet;

import java.util.Scanner;

import java.util.Set;

import javax.swing.text.html.HTMLDocument.Iterator;

public class Joy{

public static void main(String[] args) {

// Get input from the user w/ sentinel logic

Scanner reader = new Scanner(System.in);

int pairs = Integer.parseInt(reader.nextLine());

// Keep track of distances

ArrayList<Integer> distances = new ArrayList<Integer>();

while(pairs != -1){ // While still accepting input

int distance = 0;

int hours = 0;

for(int i = 0; i < pairs; i++){

String[] temp = reader.nextLine().split(" "); // Put input into a string

distance += Integer.parseInt(temp[0]) * (Integer.parseInt(temp[1]) - hours); // distance is mph times new hours - old hours

hours = Integer.parseInt(temp[1]); // keep track of current hours

}

distances.add(distance);

pairs = Integer.parseInt(reader.nextLine());

} // end while loop

// Output data to the user

for(int i = 0; i < distances.size(); i++){

System.out.println(distances.get(i) + " miles");

}

// Closed the reader

reader.close();

}// end main

}